| Intuitionistic Logic Explorer | 
      
      
      < Previous  
      Next >
      
       Nearby theorems  | 
  ||
| Mirrors > Home > ILE Home > Th. List > ax-precex | GIF version | ||
| Description: Existence of reciprocal of positive real number. Axiom for real and complex numbers, justified by Theorem axprecex 7947. (Contributed by Jim Kingdon, 6-Feb-2020.) | 
| Ref | Expression | 
|---|---|
| ax-precex | ⊢ ((𝐴 ∈ ℝ ∧ 0 <ℝ 𝐴) → ∃𝑥 ∈ ℝ (0 <ℝ 𝑥 ∧ (𝐴 · 𝑥) = 1)) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cA | . . . 4 class 𝐴 | |
| 2 | cr 7878 | . . . 4 class ℝ | |
| 3 | 1, 2 | wcel 2167 | . . 3 wff 𝐴 ∈ ℝ | 
| 4 | cc0 7879 | . . . 4 class 0 | |
| 5 | cltrr 7883 | . . . 4 class <ℝ | |
| 6 | 4, 1, 5 | wbr 4033 | . . 3 wff 0 <ℝ 𝐴 | 
| 7 | 3, 6 | wa 104 | . 2 wff (𝐴 ∈ ℝ ∧ 0 <ℝ 𝐴) | 
| 8 | vx | . . . . . 6 setvar 𝑥 | |
| 9 | 8 | cv 1363 | . . . . 5 class 𝑥 | 
| 10 | 4, 9, 5 | wbr 4033 | . . . 4 wff 0 <ℝ 𝑥 | 
| 11 | cmul 7884 | . . . . . 6 class · | |
| 12 | 1, 9, 11 | co 5922 | . . . . 5 class (𝐴 · 𝑥) | 
| 13 | c1 7880 | . . . . 5 class 1 | |
| 14 | 12, 13 | wceq 1364 | . . . 4 wff (𝐴 · 𝑥) = 1 | 
| 15 | 10, 14 | wa 104 | . . 3 wff (0 <ℝ 𝑥 ∧ (𝐴 · 𝑥) = 1) | 
| 16 | 15, 8, 2 | wrex 2476 | . 2 wff ∃𝑥 ∈ ℝ (0 <ℝ 𝑥 ∧ (𝐴 · 𝑥) = 1) | 
| 17 | 7, 16 | wi 4 | 1 wff ((𝐴 ∈ ℝ ∧ 0 <ℝ 𝐴) → ∃𝑥 ∈ ℝ (0 <ℝ 𝑥 ∧ (𝐴 · 𝑥) = 1)) | 
| Colors of variables: wff set class | 
| This axiom is referenced by: recexre 8605 recexgt0 8607 | 
| Copyright terms: Public domain | W3C validator |